During installation of a wind turbine, the maximum wind speed at which installation of the wind turbine can be carried out is a key parameter. This is particularly true for the offshore installation of a wind turbine. Offshore, a steady wind flow at an elevated level is typical. This elevated level of steady wind flow together with sporadically occurring gusts often lead to the situation that installation of a wind turbine cannot be carried out. This is a challenge, in particular as each day where installation of the wind turbine offshore has to be postponed is very expensive. Therefore, there is the general strive for enabling and ensuring installation of a wind turbine also at elevated wind speeds.
One approach of reducing the drag of a rotor blade of a wind turbine during installation has been proposed in the European patent application EP 2 669 238 A1. Therein, the drag coefficient of the rotor blade is generally reduced by covering the entire rotor blade. However, this approach has some disadvantages such as it may involve considerable costs to envelope the rotor blade entirely with the cover and to adapt the cover to the lifting device which is used for lifting the blade.
Therefore, there exists the desire to provide an alternative method to enable installation of a wind turbine even at elevated wind speeds.
This problem is solved by the subject matter of the independent claims. Advantageous modifications and embodiments are disclosed in the dependent claims.